/*
 * Copyright (c) 2010, okazoh_tk. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *  - Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 *  - Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 *  - Neither the name of the copyright holder nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#ifndef ALKES_TUNION_HELPER_H_INCLUDED_
#define ALKES_TUNION_HELPER_H_INCLUDED_

#include "alkes/internal.h"
#include "alkes/core/Memory.h"

namespace alkes {

template<class T>
class TUnionHelper
{
    enum
    {
        ARRAY_LENGTH = sizeof(T*) <= sizeof(T) ? 1 : (sizeof(T*) / sizeof(T)),
    };

public:
    TUnionHelper();
    ~TUnionHelper();

    T* initialize(uint32_t num);
    void finalize();

    T& operator[](uint32_t index);
    const T& operator[](uint32_t index) const;

private:
    bool isPointer() const { return ARRAY_LENGTH < num_; } 

private:
    union {
        T* pointer_;
        T array_[ARRAY_LENGTH];
    };
    uint32_t num_;
};

template<class T>
TUnionHelper<T>::TUnionHelper()
: num_(0)
{
    pointer_ = 0;
}

template<class T>
TUnionHelper<T>::~TUnionHelper()
{
    finalize();
}

template<class T>
T* TUnionHelper<T>::initialize(uint32_t num)
{
    num_ = num;
    if (isPointer())
    {
        pointer_ = (T*)alkes_malloc(sizeof(T) * num);
        return pointer_;
    }
    else
        return array_;
}

template<class T>
void TUnionHelper<T>::finalize()
{
    if (isPointer() && pointer_)
    {
        alkes_free(pointer_);
        pointer_ = 0;
    }
}

template<class T>
T& TUnionHelper<T>::operator[](uint32_t index)
{
    if (isPointer())
        return pointer_[index];
    else
        return array_[index];
}

template<class T>
const T& TUnionHelper<T>::operator[](uint32_t index) const
{
    if (isPointer())
        return pointer_[index];
    else
        return array_[index];
}

}

#endif
